什么意思？

#include<stdio.h>
#include<stdlib.h>
main()
{
      int a[16]={0};
      int i,j;
      a[0]=1;
      for(i=1;i<=15;i++)//一共输出十行；
      {
                       int b[11]={0};
                       for (j=0;j<i;j++)//输出每一行 ；
                       {
                       printf("%4d ",a[j]);
                       if(j==i-1)printf("\n");
                       }
                       
                       
                       for(j=1;j<=i;j++)//下一行要输出的；
                       {
                                        b[j]=a[j-1]+a[j];
                                        }
                                        for(j=1;j<=i;j++)
                                        a[j]=b[j];
                                        }
                                        system("pause");
                                        }